Flying Swallow
Page 1 of 2 12 LastLast
Results 1 to 25 of 55

Thread: Flying Swallow

Hybrid View

  1. #1

    Flying Swallow

    These are my first tries through the Paint Hangar with this aeroplane.
    My son Michael says he likes the smaller pattern better.
    I am not quite satisfied with either one. I think the pattern should be somewhere in between.

    Opinions?

    - Ivan.

  2. #2
    SOH Staff
    Join Date
    Jul 2005
    Location
    State of Confusion..... -8GMT
    Posts
    3,775
    i'm with you,
    trust your instincts.
    then, let us see the results.
    sometimes the magic works.
    sometimes it doesn't.

  3. #3
    Redding Army Airfield Allen's Avatar
    Join Date
    Dec 2007
    Location
    O85 Benton Field Airport
    Age
    36
    Posts
    5,444
    The large print look too far apart. (Too much sliver)
    "Let Being Helpful Be More Important Than Being Right!" Some SOH Founder.

  4. #4
    The reality is that most of these aircraft came in plain natural metal finish from the factory and the "Camouflage" was applied in the field in whatever pattern seemed appropriate. There are zillions of variations. Some are mostly Olive / Dark Green. Some only have a couple Green splashes of paint. Not sure which one I like better yet.

    Other than muzzles for the wing guns, this model was finished back in 2005. The camouflage has been the hangup since then.

    This aeroplane project is getting attention because of a recent article I found in "Flight Journal" magazine while grocery shopping at Wegmans. There is a place called the "Fighter Factory" down in Virginia Beach that is trying to restore one. That alone would not have changed much....

    In the article was a description of the flight characteristics of the aeroplane which was something I had never seen before. The aircraft tested was a Ki-61-I "Koh" or Ki-61-1a in Western notation. (The Japanese used the suffixes "Koh", "Otsu", "Hei", "Tei" as we do A, B, C, D for minor modifications.) I also found in a forum discussion that my original name for my model was incorrect. Apparently a Ki-61-I-KAI c never really existed. KAI is short for "Kaizo" or "modified" and is the designation used when there is a major modification to the airframe: Thus N1K1-J Shiden and N1K2-J Shiden-KAI. So this version even with major airframe modifications was really designated Ki-61-Id.

    A flight report and some additional information meant that I had to rename the project and edit the SCASM code as well.... And since I was in the SCASM code, I figured I would add an interior Canopy Frame.... and since I wanted this aeroplane to fly as closely as possible to that described in the flight report, I got back into the Flight Model....

    I also found that the locations and volumes of the Fuel Tanks was not correct, so that resulted in yet more modifications. The DP file also needed updated for weights and for firepower. It should also get a change for the large quantities of armour that I found were installed in this bird.

    A month later, everything that I can think of is up to my current standards with the exception of the camouflage.... I'm working on that now, so we shall see where that will lead.

    There are many, many surprising things about this aircraft.

    - Ivan.

  5. #5
    Quote Originally Posted by Ivan View Post
    A month later, everything that I can think of is up to my current standards with the exception of the camouflage.... I'm working on that now, so we shall see where that will lead.

    There are many, many surprising things about this aircraft.
    Now almost 4 years later, this project is no longer up to current standards.
    Technology and standards advance rapidly during wartime.

    The 3D model is still pretty much up to current standards though the camouflage still has not been done.

    The AIR File is now leaves quite a lot of room for improvement and much of this is due to better information that I now have available.
    The additional information also makes some decisions necessary because of differences between reality and how things are implemented in a simulator.

    The original flight model (Version 0.57 from July 20, 2013) was built with the assumption that the engine parameters were fairly close to the Daimler Benz DB 601Aa which was the export version of the same engine used on the Me 109E but with some improvements in boost.
    This engine was license built by both Aichi and Kawasaki for their own aircraft.
    Kawasaki had made "improvements" in their design. Unfortunately, their engine (the Ha-40) was never reliable or durable.

    The Version 0.55 flight model had a maximum Manifold Pressure of 44.5 inches Hg (as from the Me 109E) but with 2500 RPM.
    The Version 0.57 flight model had a maximum Manifold Pressure of 45.9 inches Hg and a maximum of 2500 RPM.

    The actual performance is as follows:

    Take Off
    1160 HP @ 2500 RPM with 330 mm Boost --> 45.52 inches Hg

    Normal Maximum
    1100 HP @ 2400 RPM with 240 mm Boost --> 38.976 inches Hg at Sea Level
    1040 HP @ 2400 RPM with 240 mm Boost --> 38.976 inches Hg at 4200 Meters (13,780 feet) Altitude.

    The DB 601Aa export engine had a bit higher power at low level and allowed higher RPM for Take-Off but had a bit less supercharger and thus less performance at altitude.

    The problem here is that in CFS, War Emergency Power only affects Manifold Pressure. It does not change RPM limits, so should we allow 2500 RPM as maximum or 2400 RPM? Also, should we allow a maximum boost of 330 mm or 240 mm? There is no additional power adder required to run at the higher boost; It appears to be an engine durability limit.

    One other bit of information (and the reason why this thread is worthy of an update) was a pilot report that complained that the engine did not reach a full 2500 RPM until well after take-off and the aeroplane had reached 120 MPH airspeed.
    My Version 0.57 Flight Model was only able to reach 2500 RPM at 150 MPH to 160 MPH which meant that my propeller (stock P51D) was not a good fit. The general performance was otherwise pretty good, so it was left to the next update.

    A few weeks later (still in 2013) I tried to generate some new propeller tables for this aeroplane.
    The results were quite amusing: The aeroplane would accelerate quite well initially on the take-off run until it reached 45 MPH at which point it would stop accelerating. At that point, I stopped because I clearly had no idea what I was doing.

    A few weeks ago during Spring Break, my family traveled to do a couple more college visits.
    After dinner one evening, my son wanted to try something on the Internet and we had not brought any laptop computers along, so we both went down to the public computers at the hotel.
    While he was poking around, I decided to try to work on a function that would generate the kind of graph I would need for a Propeller Efficiency Table (Record 511).
    It turned out to be fairly easy, I just saved a few notes for later use.

    A few days ago, I finally finished working on a set of Propeller Tables (511 & 512) that allow the Ki 61-I to reach 2500 RPM just as the aeroplane reaches 120 MPH. The process was actually much more convoluted but those details deserve their own thread.
    Quite a bit more tuning needs to be done, but at least one significant fault has been corrected.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Kawasaki_Ha-40.jpg   Ki61-Id.jpg  
    Last edited by Ivan; May 3rd, 2017 at 12:54. Reason: Add Some Decoration

  6. #6

    Short History

    Aichi and Kawasaki both license-built the Daimler Benz DB 601 engine.
    Kawasaki designed a heavyweight and a lightweight fighter, the Ki 60 and Ki 61, to use their engine.
    The heavyweight was intended to be the faster and more heavily armed aircraft but as the pair was developed, it was found that there was very little difference in performance between the two and that the lightweight was actually faster. The heavyweight Ki 60 was discontinued.
    The first flight of the Ki 61 was in December 1941 and a prototype actually tried to intercept the Doolittle Raid.
    The Ki 61 was not a particularly fast aeroplane especially at low altitude, so the raiders probably never knew anyone was following them.

    The design of the Ki 61, known as the Hien (Flying Swallow), was considerably different from other Japanese aircraft. It carried a significant amount of armour and was quite strongly built. Its faults were that the armament was fairly light for the time (1943) and that its engine was unreliable and lacked power. A relatively heavy airframe with very little engine power did not make for great performance.

    Germany supplied 400 20 mm MG 151/20 cannon to Japan via submarine and these were installed as wing armament on 200 Ki 61 fighters. This gave them a reasonable amount of hitting power but obviously was not a long-term solution.

    A significant redesign was made to the airframe of the Ki 61 to simplify the tail structure which also resulted in a fixed tail wheel replacing the earlier retractable version and stretched the nose section to make extra room for the ammunition boxes for a pair of 20 mm Ho-5 cannon.
    This was the kind of structural change typically noted by a Kaizo (KAI) designation change, but in this case, the eventual designation was just a change from c to d suffix (Ki 61-Id) which is the subject of this design.

    Flight performance data for the Ki 61-I series is available but most tests are of early versions. As noted earlier, engine reliability was very poor and the aircraft used for the test report I found most recently was only flown three times before it was grounded by engine failure. Late in the war when these flight evaluation were made, it probably didn't make sense to put much effort into testing an aeroplane that even at its best would only have matched technology in the ETO from about 1942.

    Maximum level speed ranged from 348 MPH to 368 MPH depending on the source but this was at a relatively low power setting of 240 mm boost and 2400 RPM.
    One has to wonder how things might have changed if the engine were more reliable and able to achieve designed power levels.

    - Ivan.

  7. #7
    Hello Ivan,
    OK, so that clarifies why there so many different colour-scheme qualities on these planes. The impression I was was getting was not totally off then!

    I like your first speckled colour scheme best, but it would also be the most difficult pattern to match at the joints between two surfaces, and the second one seems to work better there. The second one also looks clean and business-like!

    Interesting, the handling qualities you report for this aircraft. That would certainly be certainly one of its attractive qualities, apart from the superb looking lines. I hope you get the behaviour where you want it!

    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  8. #8

    Japanese Army Air Corps Markings

    Hello All,

    It has been a while because I had to do a LOT of reading to figure out what the standard markings for a Japanese Army Fighter should be.
    There are apparently a LOT of rules and almost as many exceptions to those rules.

    As noted earlier, the Camouflage pattern is much neater than it would normally be in the field which is where most of the aircraft were painted.
    This COULD HAVE been done by some obsessive mechanics who spent way too much time masking off the factory markings before painting.

    This particular aeroplane has had the national insignia on its Fuselage applied slightly larger and lower than was typical. The specification for this model was for the insignia to be 600 mm in diameter with a 75 mm white border if there was any border painted on at all.
    On a light coloured aircraft, there would usually have been no border at all but the appearance is suggested by the masking before painting.

    The standard factory overall finish was clear lacquer on upper surfaces and bare metal on the lower surfaces.
    Some photographs appear to have the aircraft in overall light gray but I don't know if this was an effect of weathering on the lacquer or actual gray paint.

    Most Ki 61 carried a white stripe on the Fuselage just ahead of the tail surfaces. This was the typical marking for a fighter aircraft, but some aircraft did not have the "combat stripe" at all or on occasion had it in other colours.
    A multi coloured strip typically indicated other service roles such as test / experimental / training but there are also fighters carrying multi coloured stripes.

    A wide white stripe would be painted ahead of the national insignia, if it were the Squadron Leader's aircraft.
    Aircraft were generally shared between pilots but some were assigned to a particular pilot and would carry personal markings or emblems.

    The Sentai emblem was typically painted on the Fin and Rudder and each Sentai (made up of 3 squadrons or Chutai) would typically have its own symbol though each Chutai within the unit would have the symbol in a different colour.

    The biggest problem I ran into here was that although 10.24 feet / 256 Pixels is a very fine scale for Combat Flight Simulator, it does not allow very fine detail to be painted.
    My original idea was to include a typical Japanese Chrysanthemum but when reduced down to the 30-35 Pixels available on the Fin, it more like a gray blur. A Plum Blossom (Ume) crest (Mon) was also considered and I am still working on that idea.
    My children told me that the first versions looked more like a reel of movie film!

    The emblems for the 19th Sentai and 68th Sentai were fairly simple so I just used those symbols for now.
    The 244th Sentai markings with Red or Blue Tails are the typical markings seen on artwork depicting the Ki 61 so I am reluctant to go down the path of least originality.

    Also included is a screenshot of my Macchi C.202 Folgore that was released a couple years back. My preference is for markings with the style typical of the particular air force but not representing any actual historical aircraft or unit. I do not believe the Squadriglia emblem on the Folgore was ever carried by an actual fighter.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Ki61-68Sentai.jpg   Ki61-68Sentai2.jpg   Ki61-19Sentai.jpg   Macchi202.jpg  

  9. #9
    Hello Ivan,
    What ate up the camo?
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  10. #10
    Hello Ivan,
    It looks very realistic, and the spread is nicely uniform and balanced. The effort seems to have been quite worth while!

    Your previous speckled pattern and also this one, are the two that in my opinion look the best on this plane.

    I noticed on several original photographs that there seem to have been perhaps 4 or 5 different camo patterns, some of which look terribly botched, as if the crew had done a last-minute job themselves with spray cans just before covering the planes a bit with palm leaves!
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  11. #11
    Hello Aleatorylamp,

    I am fairly pleased with how the camouflage turned out.
    I still have trouble with random patterns. It probably comes from my obsessive compulsive side which drives me to try to make things "exactly" as I think they should look. When there is no "exact" and no distinct "should look", I have difficulty because I can't really tell when I am done or where to improve things.

    The Kawasaki Ki 61 was completed at the factory and painted with national insignia, IFF stripes, various stencils, and I believe they typically had a red star around the wing gun openings. That was it.
    The appearance would be pretty much like the overall Gray / Natural Metal finish that I had when this painting exercise began.

    Most Ki 61 would have been crudely painted in the field by whatever means the locals could come up with.
    Sometimes the appearance was good. Sometimes it was a mess. Sometimes they masked around the factory paint. Sometimes they just painted around the factory paint in a very crude manner.
    This crude painting method is probably why the canopy frames were never painted; it would take too much effort to mask around the canopy glass.
    Some of the camouflage looked a lot like it was done with a broom or mop.

    From what I have seen, the unit markings were generally VERY well painted as were additional decorations such as stripes and lightning bolts or kill markings and other personal emblems.

    I am sure some of the personnel in the field masked and painted carefully around the insignia and the home defence aircraft such as from 244 Sentai tended to be painted very precisely.

    I don't think my camouflage pattern is all that realistic looking but the look I was trying to get was that of the aircraft that were painted with lots of overlapping green stripes with a spray gun. There were some gray patches left over but they tend to be much smaller than what I have here. (No, I did not contradict myself. I don't think it is particularly realistic but I still like the appearance.)

    My current task is to go back and edit the flight model to improve the handling characteristics.
    By reputation this aircraft and its descendants were some of the nicest handling of the Japanese fighters and right now, this bird does NOT handle all that well.

    An accelerated stall is absolutely vicious and a snap roll happens often without even trying. Low speed control is quite poor, and controls in general is not very precise.
    This part of adjusting flight models is actually quite fun because it isn't just a matter of flying on autopilot and recording numbers.
    As I mentioned in the past, my test is to see if I can fly Figure Eights through the base of the Eiffel Tower very easily. With my P-40s and FW 190A, this is very easy. With the Hien, it isn't easy at all but it should be.

    The negative curves in the Power Coefficient Table should also be adjusted a bit in my opinion. You probably don't know this, but the ones in your Two-Pitch propeller probably make more sense than what I currently have in this AIR file.

    - Ivan.

  12. #12
    Hello Ivan,
    Sit, Fido!! Good Dog... and all night!

    Anyway, your thorough testing and fine-adjustments,
    together with the intricate textures and excellent lines
    this model shows, will surely make it a very successful
    model in the warbirds library - not to mention the
    performance!

    Nice work!
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  13. #13

    Edits and Tests

    I tried to do just one more edit in AF99 and got the result shown in the screenshots.
    I do not believe it is the result of a broken Development Machine, but I also know that MdlDisAs did not work either and THAT is most certainly a misbehaving Development Computer.
    I will try the SCASM (MdlDisAs) edit on another computer this evening and see if it works there.

    On another somewhat related note, I also found that the Roll Rate was not quite what I expected it to be and Trim appears to be not quite stable.
    I suppose it will be yet more editing on the AIR file.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Ki61_Barf1.jpg   Ki61_Barf2.jpg   Ki61_Barf3.jpg  

  14. #14
    Hello Ivan,
    I have been following your posts with great interest, and I´m glad you are making progress on your Ki-61 - especially as you say it has the first CV propeller that your workshop has produced!
    Despite conflicting information, which is mostly inevitable and which I always find when preparing my models, it seems that with your reasoning to interpret the data, you are achieving a very good flight model.
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  15. #15
    Hello Aleatorylamp,

    I am glad you are enjoying the thread. I figure there are probably about a half dozen people actually following it.

    Yes, this was the first propeller from Ivan's Prop Shop.
    There are lots of issues which I am finding which I have only hinted at here.
    You can see the Record 511 Efficiency Graph I am using.
    Compare it to the Stock P51D Graph and you will see a lot of the things I mentioned in your FW 200 Thread.
    You can also see an illustration of the "Interpolation Problem" which I described many times.
    It gets pretty bad at 32.5 degrees and at 37.5 degrees.

    I don't want to correct the situation at 32 degrees because it will raise the Sea Level speed and possibly push the best climb speed even higher than it is now. The Best Climb Speed at 180 MPH IAS is already higher than I would have liked; Ideally I would have wanted it down around 150 MPH or possibly 160 MPH and perhaps then the Service Ceiling would have been higher.

    Correction to History Comments:
    800 MG 151/20 cannon were delivered by the Germans. They were installed in 388 aircraft (obviously with a few spares).

    It is interesting to compare the performance of fighters using the DB 601A / DB 601Aa series of engines.
    The standard engine on the Messerschmitt 109E was the DB 601A.
    The critical altitude of the DB 601A was 4500 Meters.
    The Germans did not export the DB 601A. For Export aircraft / engines, they used the DB 601Aa engine.
    The critical altitude of the DB 601Aa was 3700 Meters.
    The DB 601Aa engines were "license-built" by Alfa Romeo of Italy, Aichi and Kawasaki of Japan.
    The Italians pretty much stuck with the original German design with very minor improvements.
    The Italian engines were apparently pretty comparable with the German originals but with a reputation for a bit better durability.
    The Japanese (Kawasaki) used the basic DB 601Aa design but made some "improvements" for their Ha-40.
    The maximum boost was increased very slightly but the critical altitude was increased to 4200 Meters which is almost as good as the original non-Export DB 601A.
    The engine was also lightened over the original.
    The reliability and durability however were much worse than the original design.
    The aircraft that was the test subject for the pilot report I found apparently was grounded after its third test flight because pieces of the engine's main bearings were found in the oil.

    Some German Messerschmitt 109E's were also equipped with the DB 601Aa instead of the DB 601A and thus make a good comparison the Macchi C.202 and Ki 61-I.

    Some numbers:
    Messerschmitt 109E------ 354 MPH ---- 34,000 Feet Service Ceiling
    Macchi C.202 --------------375 MPH ---- 37,000 Feet Service Ceiling
    Kawasaki Ki 61-I --------- 368 MPH ---- 38,000 Feet Service Ceiling

    On a different note, The Paint situation is coming along fairly well at least for what I have done thus far. The Wings and Stabilisers were easy because they do not need to be matched to anything. The Fuselage extends across about 5 or 6 different texture files so matching the patterns will not be fun.

    Incidentally, the scales I am using are:
    Fuselage --- 10.24 Feet over 256 Pixels
    Wings ------ 18.20 Feet over 256 Pixels
    Stabiliser -- 12.80 Feet over 256 Pixels
    Fin --------- 10.24 Feet over 256 Pixels

    The Wing Fillet is an odd size but will be worked at whatever scale necessary to blend patterns.
    It is amusing that from the Virtual Cockpit view, the Fuselage cannot be seen, so it look from there that nothing more needs to be done.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Ki61-WingsPainted.jpg   Ki61-VCockpit.jpg  

  16. #16
    Hello Ivan,
    I was a bit curious about possible effects, if any, of the 150 lb aft fuel tank.
    Maybe it is a silly question, and would perhaps depend on whether this tank was intended to be used first or last - i.e. as reserve.

    Would the added weight behind the CoG have to be compensated with an offset parameter, or is a slight tail-heaviness desirable until the fuel there is consumed? Of course if this were negligible, it could of course go ignored.

    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  17. #17
    SOH Staff
    Join Date
    Jul 2005
    Location
    State of Confusion..... -8GMT
    Posts
    3,775
    granted, it's 03:15 and i'm in a bit of a fog.
    but, if the original ammo count was 150 rounds per gun
    and the corrected load is actually 120 rounds per gun,
    wouldn't you need to subtract instead of add 31 pounds
    to correct the loaded weights,
    or am i missing something here?

    okay, i'm going back to bed
    sometimes the magic works.
    sometimes it doesn't.

  18. #18
    Hello Ivan,
    Meticulous work on the wing and tail textures - looking fantastic!
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  19. #19
    SOH-CM-2019
    Join Date
    Sep 2011
    Location
    St Simons Island GA
    Age
    70
    Posts
    2,322
    Blog Entries
    1
    Thanks for posting the results of your efforts. One of Japan's prettiest WWII fighters. Following with interest!

  20. #20
    Thanks Guys,

    I had actually hoped to do the full series of fighters from the Ki 61-I to Ki 61-II-KAI to the bubbletop Ki 61-II and finally the Ki 100 in both the -Ko and -Otsu versions. So far, I have not gotten past Part 1 of the series yet.

    I had originally not wanted to build the Ki 61 because it really is at best only an adequate fighter for its time, but it really was a beautiful aeroplane and I had never seen a really good CFS version out there. My combat flight testing of this aeroplane was against my own Spitfire Mk.IX with a stock flight model and I figure it has about a zero percent chance of winning such a fight. The stock Griffon-powered Spitfire Mk.IX has about double the engine power in an aircraft that is pretty near the same size and weight. (Yes, I did say "Stock Griffon-Powered".)

    From a tactical standpoint, I figure the Ki 61-I was equivalent to the pre-production Me 109F or about even with a Macchi C.202 which meant that by 1944 when the Ki 61-Id was introduced, it was outclassed. That is why I was hoping to get to its successor that never arrived, the Ki 61-II-KAI which was pretty much equivalent to Me 109G series.

    From a flight model standpoint, the issues to work with are these:
    Propeller Pitch Range is 27 - 47 degrees.
    The engine reaches full 2500 RPM at around 120 MPH.
    That means that it comes off its low pitch stop at around 120 MPH.
    At the moment, it is hitting best climb at around 180 MPH with around 30 degrees Propeller Pitch.
    The problem is that with the way CFS Propeller graphs are arranged, the 5 degree intervals (actual graphed angles) are the peaks and the areas between (2.5 degree intervals) are the valleys and it would take a lot of messing around to bring the airspeed for best climb down to 150-160 MPH where I think it should be.
    This kind of thing will be discussed further if I ever post a "Propeller" thread.

    The painting is coming along rather badly. I found that I had lost some detail with the method I am using and need to do a few things over again.

    Ivan's Paint Shop is not very qualified which is why so many project end up getting trapped there.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Ki61-1d-WireFrame.jpg  

  21. #21
    Hello Smilo, hello Ivan,
    If I understand the weight from the bullet count correctly,
    the 31 lb from the rounds reduction deducted from the DP
    file would have to be compensated in the total weight count,
    so they would be added to the dry weight in the the .air file.

    I don´t know if the Dp file gun position is also the position
    of the ammo weight, and whether it affects the CoG. If it does,
    depending on the gun positions (nose or wing - or both, as the
    screenshot seems to show), this would be
    another factor that
    could alter the CoG, as well as the 150 lb
    aft tank.

    Cheers,
    Aleatorylamp
    Last edited by aleatorylamp; January 28th, 2018 at 06:24.
    "Why make it simple if you can also make it complicated?"

  22. #22
    Hello Gentlemen,

    Aleatorylamp is correct in his explanation of the DP file subtraction to be compensated for in the AIR File.
    The problem here is that I already made the change to the DP file a long time ago and did not reflect the change in the AIR file because I did not make a corresponding change in my spreadsheet to calculate weight and everything still looked right.

    Regarding the Aft Fuel Tank:
    My original intent was to not put in the Fuel Tank at all because I was not sure about the volume and also because I do not have a proper fuel selector to let me access 4 tanks.
    A few months ago, I found that my original estimate of the volume was actually correct and that the Aft Fuel Tank was connected to the Center Wing Tank and thus needed no extra selector.
    In reality the actual selector is a bit more complicated but I have no ability to program mouse functions and thus can't build a correct fuel selector.

    The "New" Fuel Tank is really just 95 liters greater capacity in the Center Wing Tank, so there is very little change in gravity.
    This will also require some change to the Check List.

    Regarding Fuel Tank locations and Center of Lift, I have an idea in mind about how things really work, but have not figured out a proper way to test my theory yet.

    When I made these changes, I did a few quick flights and was surprised by how slow the Roll Rate was.
    I will have get a stopwatch and go back to correct this.

    - Ivan.

  23. #23

    More Flight Model Updates

    Recently I found that the Zero Boost value for Japanese Engines was actually 760 mm Hg instead of the 750 mm Hg that I had been using. The discrepancy isn't much but I thought it was necessary to edit the AIR file to reflect the changes.

    The effect is essentially increasing the Manifold Pressure limits by 10 mm (0.39 inch) Hg and then adjusting other factors to compensate so that aircraft performance is unchanged.

    The first test was to observe the differences resulting in a simple increase in MP with no other changes.
    At the 500 foot test altitude, the difference was not much: +10 HP.
    Next came the obvious adjustments to Friction and then Torque.
    I decided that the following test altitudes would be useful for comparison of performance changes:

    Initial Test Settings were
    38.97 inches Hg - 2400 RPM
    500 feet........1046 HP............This is the baseline tuning Target
    12500 feet....1153 HP.............This is slightly under the Engine Critical Altitude
    15000 feet....1114 HP.............This is Aircraft Critical Altitude
    25000 feet.....757 HP..............This number is just an intermediate point to confirm shape of the power curve
    30000 feet.....611 HP..............This value is near but still under the Service Ceiling

    The three numbers that are the most important are:
    500 feet ----- This is where we determine Sea Level Speed.
    15000 feet -- This is where we expect to achieve Maximum Level Speed.
    30000 feet ---This determines Service Ceiling.

    Once we have those three numbers matching the original values, the performance should also be pretty similar and not require any modification of other sections of the AIR file.

    The first edit of just the Friction graph brought the power output for 500 feet and 12500 feet very near the target values, but as noted in the Engine Tuning Tutorial, the altitude performance fell off sharply.

    Next was an adjustment to Engine Torque which brought the power down very significantly and needed to be compensated for by adjusting Friction downward by quite a bit.
    The power output (1102 HP) at 15000 feet was still a bit lower than it should be although other numbers were very close.

    A slight adjustment of the Supercharger Boost Gain from 2.25 to 2.27 gave a result that I believe was a better match

    Final Test Settings were
    39.37 inches Hg - 2400 RPM
    500 feet........1048 HP............ + 2 HP is negligible for performance.
    12500 feet....1154 HP............ + 1 HP
    15000 feet....1115 HP............ + 1 HP
    25000 feet.....761 HP............ + 4 HP
    30000 feet.....616 HP............ + 5 HP

    - Ivan.
    Last edited by Ivan; February 28th, 2018 at 10:49.

  24. #24

    Modifications for Service Use

    In doing my basic research for the Ki 61-Id, I had not looked much at what was done with prior versions of this aircraft in service use. I was more interested in the aircraft models as they came from the factory.
    The Ki 61-Id was lengthened to provide space in the fuselage to mount a pair of 20 mm Ho-5 cannon.
    It also carried substantially more armour than prior versions and came with an Aft Fuselage Fuel Tank as standard.

    The Ki 61-I in all versions was somewhat under powered. With prior versions, often a fair amount of the armour was removed in service use to lighten the aircraft for better performance especially at altitude.
    Some units also chose to remove the Aft Fuel Tank because its use moved the aircraft Center of Gravity too far aft and was believed to be the cause of many accidents.
    This was my original reasoning (and the fact that there was no proper fuel selector) for leaving out the Aft Fuel Tank. The capacity of this tank in Ki 61-Id was only 95 Liters but was 200 Liters in earlier versions that were equipped with the Aft Fuel Tank.

    - Ivan.
    Last edited by Ivan; February 28th, 2018 at 10:51.

  25. #25
    Hello Ivan,

    From your comment on the Fw200 Condor thread, whose content has recently largely also been propellers, I´m glad that you have managed to get a reasonably good working propeller for your Ki-61.

    Although the Ki-61 is on a different power level compared to the "Stock Griffon-Powered" Spitfire - i.e. the greatly souped-up Merlin (stock plane performances cheating again, are they?)..., at least this so-to-speak "bench test" proved that the propeller behaved very bravely, and seems to have achieved quite a congratulatable result - at least for now!

    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

Similar Threads

  1. A Swallow for FSX
    By RyDraiggoch in forum FSX General Discussion
    Replies: 24
    Last Post: February 20th, 2021, 12:52
  2. Flying the P-40
    By Naki in forum Ickie's NewsHawks
    Replies: 4
    Last Post: May 3rd, 2017, 17:56
  3. RE: How's this for flying a DC-4?
    By brad kaste in forum Ickie's NewsHawks
    Replies: 2
    Last Post: March 21st, 2012, 10:51
  4. Little known Moth family member released: DH-81 Swallow Moth
    By Maarten - in forum FS 2002/2004 General Discussion
    Replies: 3
    Last Post: June 12th, 2011, 05:39
  5. Ito's New De Havilland DH.108 Swallow
    By Flyboy208 in forum FS 2002/2004 General Discussion
    Replies: 23
    Last Post: October 17th, 2008, 12:35

Members who have read this thread: 0

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •